Update docs with info on running demos locally

Hi, I wanted to make use of your Atto library, but I had trouble getting the demos to run as static files on my PC. I've since worked it out and wanted to share my findings. I've updated the README to include a section on getting the demos running.
Some things to note:
* I've listed example directories assuming a Windows PC, since that's what I used.
* I don't have proper instructions for installing the Good Dog font, since the stylesheet.css seems to be something custom for the buyog.com website.
Also, since test.js is required with require.js, is there an equivalent for curl, or does it automatically handle the text include?